Add CrcTransformer for checksum calculation

[das-Abroxas]

This PR implements CRC checksum calculation support to enable data integrity validation for S3 uploads. By utilizing the crc-fast crate, the new CrcTransformer supports all known CRC-32 and CRC-64 variants.

Changes

• Added crc-fast dependency for efficient CRC calculations
• Implemented CrcTransformer with support for CRC32, CRC32C, and CRC64NVME algorithms
• Added comprehensive unit tests for all three CRC algorithms, multifile situations and combination with other transformers

Testing

All unit tests pass and verify correct checksum calculation for known input data across all three supported CRC algorithms.

Closes #218

[codecov]

Codecov Report

❌ Patch coverage is 95.88477% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 36.49%. Comparing base (9a10bc7) to head (75e2e68).
⚠️ Report is 14 commits behind head on main.

Files with missing lines	Patch %	Lines
...ata_proxy/src/s3_frontend/utils/crc_transformer.rs	95.88%	5 Missing and 5 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #224      +/-   ##
==========================================
+ Coverage   35.69%   36.49%   +0.80%     
==========================================
  Files         127      128       +1     
  Lines       17583    17826     +243     
  Branches    17583    17826     +243     
==========================================
+ Hits         6276     6506     +230     
- Misses      10532    10540       +8     
- Partials      775      780       +5     

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[St4NNi]

Nice addition, as usual the whole transformer stuff is error prone. So there are a few things to look out for.

[St4NNi]

I think there could be a race condition between receiving a file context and process_bytes. Maybe its best to assert this and fail if there is no file context when processing bytes.

[das-Abroxas]

The fact that message and byte processing run asynchronously is a fundamental problem of the implementation of the Pithos library, not the transformer.

Of course, additional checks could be built in for this, but that would add a considerable degree of complexity that would not be relevant for our default use case.

[St4NNi]

This looks good now ! Approved !